Clinical evaluation of subjects, particularly those with non-specific symptoms such as chest pain or discomfort, shortness of breath, nausea, vomiting, eructation, sweating, palpitations, lightheadedness, fatigue, or fainting, can present significant challenges, as the cause and severity of the subject's condition may not always be apparent. The decision whether to treat a subject aggressively or conservatively, or to admit the subject as an inpatient or to send them home, may sometimes be made solely on a physician's clinical assessment or “gut feeling” as to the individual's actual condition. Biomarkers that indicate a subject's likelihood of an adverse outcome, e.g., mortality, and/or the presence of severe disease, would significantly enhance the physician's ability to make informed treatment decisions.